Technical field
[0001] The invention relates to antimicrobially active agent for building industry, method
of its production and use.
Background of the invention
[0002] Problem of presence of microorganisms such as bacteria, yeast, (one-celled fungi),
moulds (fibrous fungi), fungi, mosses, lichens on exteriors and in interiors of buildings
and on various constructions, or nostocs, algae (primitive plants) at water plants
and dams, in water and sewage pipelines, is serious not only in regard of hygienic,
health and aesthetic issues, but also in regard of bio-deterioration of building materials.
Their presence is conditioned to appropriate temperature and humidity conditions,
depends on pH of environment, presence of oxygen, radiation, etc.
[0003] Biologic corrosion of concretes and mortars is caused by organic and inorganic acids,
which arise by effect of mainly bacteria particularly sulfuric and nitrifying (oxidizing),
which effect on hydrogen sulfide H
2S creates even sulfuric acid H
2SO
4 and on ammonia NH
3 nitric acid HNO
3, which belong to the strongest inorganic acids. By effect of other kinds of bacteria
high-molecular organic acids are produced, such as humic acid or pyruvic acid and
low-molecular organic acids such as formic acid, acetic acid, propionic acid, butyric
acid, lactic acid, oxalic acid, malic acid, citric acid and others. These acid metabolites
react in concretes and mortars mainly with calcerous components of concrete and mortar
stone with development of their non-binding calcerous salts, thus causing degradation
of the stone into its depth. In some cases, they can react also with components of
aggregates, in some cases with admixtures and additives.
[0004] The danger of attack of concretes and mortars by microorganisms is increasing when
using organic additives (polyvinylacetate, casein, methyl cellulose, lignosulphonate
and so), or admixtures (scutch, sawdust, wood powder, wood chips, wood wool, wood
fibers, split-wood and so). In regard of moulds, besides biochemical deterioration,
mechanical deterioration comes along, e.g. by growth of their hyphae through volume
of harden stone. Stone structure is deteriorated, in some cases even destroyed.
[0005] Antimicrobial protection of the buildings and constructions, or places with presence
of microorganisms (damp masonry, building bases, etc.) or places with their ladleential
occurrence (hospitals, schools, kitchens, pools, laundries, hygienic facilities, stores,
industries like food industry, meat processing, distilleries, pharmaceutics, cosmetics,
chemical, wood processing, various bio-productions, agriculture, rendering plants,
water treatment corporations, sewage, waste water treatment plants, cooling towers)
is thus very important.
[0006] To prevent presence, growth and reproduction of microorganisms, biocidal additives
are added to concretes, mortars, plasters, cement glues, wooden constructions and
wood-containing products (
Bajza, A. and Rouseková , I., Technológia betónu /Technology of concrete/, Jaga, Bratislava,
pgs. 70 and 156, 2006), that provides the building materials for bacteriocidal, bacteriostatic and fungicidal
and fungistatic properties. However, these solutions are very expensive including
high purchase and operation costs and along with that, many of biocidal additives
possess only selective antimicrobial effect, not covering wide spectrum of microorganisms,
the most of them is by effect of alkali environment of the hydrating concrete or mortar
stone instable and has short time effect only.
[0007] Majority of biocidal additives contain organic compounds as antimicrobially active
constituent. Market offers enormous number of antibacterial and anti-mould preparations,
which, however, are not the object of the invention.
[0008] Disadvantage of currently used biocidal additives is, that majority of them has only
selective antimicrobial effect, not covering wide spectrum of microorganisms, many
of them are instable and have short time effect only and the biggest disadvantage
is their price, because these preparations are costly. Even also investment costs
for storage equipment, batching, mixing and homogenization in cement and cement containing
mixtures and also operation costs are added to this price. Effect of biocidal additives
is affected by their solubility in water and method of their application. Additives
well soluble in water, after mixing water adding, are easily washed up from fresh
concrete and cement containing mortar and loose their effect relatively quickly. Additives
less soluble in water can, after longer time, diffuse to the surface from the hydrated
stone and as well loose their effect relatively quickly.
[0009] Majority of biocidal additives decomposes by effect of alkali environment of hydrating
concrete or mortar stone. In many cases, conventionally available biocidal additives
are not suitable for building materials. However, exceptions exist, such as
US 7223443,
US4556426, RO 000000120968,
JP 2005255551,
JP 11012017,
JP 03271206.
[0010] As another possibility appears the use of organic compounds with bound metal ion
such as Cu
2+, Zn
2+, Ca
2+, Ba
2+, dosing in amount of 0.025 to 2 % (by weight),
WO 2006065259. Biocide can be added either in the form of powder, or can be bound in porous glass,
ceramics, mineral or polymer with time sequential release of biocide. Combined organic-inorganic
composite material composed of organic polymer with antibacterial and antifungal functional
group, to which an inorganic part containing bivalent metal ion is bound, can also
be used, according to
JP 2002235008. As another carriers of antibacterial agents can also be particles of metal, glass,
glass-ceramics,
WO 2006064060, onto which oxide, oxide nitride, oxide carbide, nitride, carbide layer with content
of antibacterial agent Ag
+, Cu
2+ a Zn
2+, is applied in the form of inorganic compounds or metals. Besides powder glass with
content of Ag
+, Zn
2+ a Cu
2+, the carriers of Ag
+, Zn
2+ a Cu
2+ in antimicrobial agents can also be zeolites,
US 6924325, zeolite mineral mordenite (Ca,Na
2,K
2)Al
2Si
10O
24.7H
2O according to
JP 08109108, ceramics on the basis of ignited calcium phosphate Ca
3(PO
4)
2 and feldspars according to
JP 08259298, calcium phosphate compounds according to
JP 06024919, crystalline or amorphous TiO
2 according to
JP 2001106607. Also alone pure TiO
2 with photo-catalytic ability in the crystalline, amorphous forms, as fibrous, monoclinic,
rutile, anatase can be used as antibacterial agent for cements according to
JP 2000219564. Antimicrobial agent for cements can also be based on nickel Ni amorphous alloy applied
on organic or inorganic nano and micro particles according to
JP 09221347. Antimicrobial agent for cements can also be based on ammonia salts according to
JP 2003292358. Fungicidal blended material suitable for fungicidal cements other than silicate
gray and white can also be based on minerals of alkaline metals, alkali earth metals,
non-metallic minerals and rare minerals in combination with zeolites, boron minerals,
clays, kaolin, bentonite, acidic clays, apatites, sulphates of aluminium, zinc, calcium,
barium, carbonate of strontium, oxides of zircon, sodium, lanthanum, cerium and neodymium,
in which fungicidal effect is induced by ions of rare minerals, and which are added
to cements in amount of 3 to 20 % according to
JP 11302058.
[0011] From currently known antimicrobial effective mixtures having high content of CaO
and glassy phase there is bioactive glass from the system SiO
2-Na
2O-CaO-P
2O
5 in the form of nanoparticles, which by contact with water solutions release active
ions in time sequentially, create alkaline environment having antimicrobial effect
(
Waltimo, T. et al., J. Dent. Res., 86, (8) pgs. 754-757, 2007). Releasing of Na
+, Ca
2+ ions and inclusion of H
3O
+ protons to glass structure raises pH of environment. Antimicrobial effect is increased
also by releasing of SiO
2. They are used especially in dental medicine and orthopedics. Antimicrobial effect
of bioactive glasses can be increased by doping with Ag
+, which has wide spectral antimicrobial effects (
Verné, E. et al., Biomaterials, 26:25, pgs. 5111-5119, 2005)
[0012] Antimicrobial glasses can have various chemical compositions, e.g. antimicrobial
glass from system Ag
2O-ZnO-CaO-B
2O
3-P
2O
5 with slow releasing of Ag
+ ions,
US 6831028. Also B
2O
3, Al
2O
3, MgO, K
2O, CaF
2 can be associated to the system SiO
2-Na
2O-CaO-P
2O
5, and to which Ag
+, Cu
+, Cu
2+ and Zn
2+ ions are added,
WO 2000015167 and
US 7241459. Fluorides are basis for fluoroaluminatesilicate glasses SiO
2-Al
2O
3-F
- so called glass-ionomer cements used especially in dental medicine, which are able
to set and harden in water environment,
US 6765038. Glass-ionomer cements are composed of alkali and acid, which after mixing, react
producing water and fluoride salts. Due to long time release of fluorides F
- and the change of pH of environment, they belong among antimicrobial agents.
[0013] In cosmetics, soluble glass based on B
2O
3, SiO
2, Na
2O, Ag
2O or P
2O
5, CaO, Al
2O
3,Ag
2O or P
2O
5, MgO, Al
2O
3, Ag
2O, or P
2O
5, K
2O, CaO, CuO, containing at least one ion of domain Ag
+, Cu
+, Cu
2+ or Zn
2+ are used,
US 5290544 and
US 57666111. Ions released to water solution provide for long time antibacterial and antifungal
effect without negative impact on skin.
[0014] However, through centuries used lime CaO, lime hydrate Ca(OH)
2 respectively, as such posses antimicrobial effect, what is exploited e.g. in elimination
of microorganisms from waste water (
Grabow, W., O., K. et al., Applied and Environmental Microbiology, Vol. 35, No. 4,
(8) pgs. 663-669, 1978). Antimicrobial effect of materials with content of Ca(OH)
2, such as e.g. Ca(OH)
2/salicylate cements, depends on speed of releasing hydroxyl ions OH
- out of slowly soluble Ca(OH)
2, and thus on pH of environment. (Vuja

ković, M. and Radoslavjević, B., Serbian Dental J., Vol. 53, pgs. 104-111, 2006).
Increase of pH>9 prevents growth and biological activity of microorganisms.
[0015] Common portland cements, produced in huge amounts worldwide, belong to calcium silicate
cements and by their chemical composition they belong to the system CaO-SiO
2-Al
2O
3-Fe
2O
3. They are produced from portland clinker, which chemical composition is characterized
by various ratio of these four main oxides being 55 to 70% by weight CaO, 16 to 26%
by weight SiO
2, 4 to 8 % by weight Al
2O
3 and 2 to 5% by weight Fe
2O
3, which mutually react at high temperatures, on the order 1450 °C, producing main
clinker minerals in amounts in the range of 50 to 85% by weight of alite C
3S, 15 to 30% by weight of belite C
2S, 5 to 15% by weight C
3A and 5 to 15% by weight C
4AF (C=CaO, S=SiO
2, A=Al
2O
3, F=Fe
2O
3, M=MgO, P=P
2O
5, H=H
2O, N=Na
2O, K=K
2O), with high content of bound lime a small content of free lime CaO up to 2% by weight.
Part of given CaO reacts to Ca(OH)
2 during hydratation of clinker phases according to reactions (1-3), which crystallizes
as portlandite and of course OH
- groups are released into the solution, which during setting of portland cement increase
pH of environment and have antimicrobial effects, what is exploited in elimination
of microorganisms from waste water by use of lime CaO, lime hydrate Ca(OH)
2 respectively (
Grabow, W., O., K. et al., Applied and Environmental Microbiology, Vol. 35, No. 4,
(8) pgs. 663-669, 1978).
CaO + H
2O → Ca(OH)
2 (1)
C
3S + H
2O → C-S-H (gel) + Ca(OH)
2 (2)
C
2S + H
2O → C-S-H (gel) + Ca(OH)
2 (3)
[0016] These antimicrobial effects of hydrating phases are by their re-crystallization during
hardening completely lost over time and thus already substantially hydrated concrete
or mortar stone can be attackable by microorganisms.
[0017] To calcium silicate cements belong also all cements with additives and admixtures
according to European standard EN 197-1: 2000, especially cements such us white and
colored cements with lowered content of C
4AF, sulphate-resistant cements and road cements with lowered content C
3A, belitic cements and cements having low hydrating heat and with low initial strength
development with higher content of C
2S, mortar cements for masonry and plastering.
[0018] To special group of cements with low volume of production belong aluminous cement,
in some cases also small group of cements based on phase 3CA.CaSO
4, so called sulphoaluminate-belite cements, which volume of production is however
negligible.
[0019] Main phases of aluminous cements are calcium aluminates and among them especially
CA phase, others are C
12A
7, CA
2 and C
2AS, C
2S. These cements hydrate very fast without releasing Ca(OH)
2.
[0020] But aluminous cements are used, due to their characteristics of fast setting, in
the special mixtures with possibility to add antibacterial additive. As an example
it can be dry plastering mixture with content of aluminous cement, sand and antibacterial
additive according to
JP 2006335597, hydraulic mixture containing calcium aluminate glass and antibacterial metal from
group Zn, Cu, and\or Ag according to
JP 2003206163, antibacterial and antifungal expansional agent based on free lime, anhydrite, hauyne
(hauyne mineral (Na,Ca)
4-8Al
6Si
6(0,S)
24(SO
4,Cl)
1-2), calcium ferrite, calcium aluminoferite, calcium silicates and one or more representatives
of group CuO, ZnO, or Ag
2O according to
JP 2002087861.
[0021] Sulphoaluminate belite cements are used for expansive cement mixtures also with possibility
of antibacterial additive. As an example it can be grouting mortar with expansive
agent based on 3CA.CaSO
4 and antibacterial carbon fibers according to Korean patent
100600440, painting mixture based on white cement, 3CA.CASO
4, metakaoline, CaCO
3, SiO
2, polyacrylate and Ag
+ nanoparticles according to
JP 1020060055116.
[0022] Special group are calcium phosphate cements used in dental medicine and orthopedics
having main phases from system CaO-H
3PO
4-H
2O, setting by acid-base reactions. Here belong hydroxyapatite cements
EP 0639366 based on hydroxyapatite Ca
10(PO
4)
6(OH)
2 and other calcium phosphates such as tetracalcium phosphate (diphosphate tetracalcium)
Ca
4(PO
4)
2O, amorphous and crystalline α- and β- tricalcium phosphate (phosphate tricalcium)
Ca
3(PO
4)
2, dicalcium phosphate dihydrate CaHPO
4.2H
2O, dicalcium phosphate CaHPO
4, monocalcium phosphate monohydrate Ca(H
2PO
4)
2.H
2O, monocalcium phosphate Ca(H
2PO
4)
2, octacalcium phosphate Ca
8H
2(PO
4)
6.5H
2O, they can further contain CaO, Ca(OH)
2, CaCO
3. Antimicrobial additive, e.g. with organic base
US 5968253, can be added to them. Antimicrobial properties of calcium phosphate cements on the
basis of Ca
4(PO
4)
2O and Ca
10(PO
4)
6(OH)
2 are even higher than with Ca(OH)
2/salycilate cements, due to production of amorphous Ca(OH)
2 during their setting, which has higher solubility, than with Ca(OH)
2/salycilate cements and thus also more OH
- groups are released to the environment (
Gbureck, U. et al., J. Biomedical Mat. Res. Part B: Applied Biomaterials, Vol. 83B,
No. 1, pgs. 132-137, 2007).
[0024] All these current solutions, however, are very expensive regarding to high purchase
prices of biocidal additives, they require investments to production equipment, such
as e.g. storage tanks, batch equipment, blending centers etc., they are associated
with high operation costs, with threat of non-homogeneous distribution of antimicrobial
additive within cement or cement containing loose matrix of building material, because
amount of antimicrobial additive is several times smaller, and also threat of segregation
of antimicrobial additive is present during transportation and especially in mixture
with water in application of building material at desired location.
[0025] It would be advantageous to obtain generally available antimicrobial active agent
for building industry, which could serve as additive, admixture or other component
for cements, building binders, cement containing mixtures, building products and building
materials with increased antimicrobial effects, and without investment costs and without
a raise in operational costs, with good homogeneity in the mixture, without possibility
to segregate in the fresh cement and mortar mixtures with water. It was discovered,
that said suitable material for building industry are metallurgical slags.
Summary of the invention
[0026] Metallurgical slags are obtained as by-products in the production and processing
of metals. There are granulated blast-furnace slags, air-cooled blast-furnace slags,
steel slags, ladle - calcerous slags and slags scrapped in production, processing
and refining of non-ferrous metals. The broadest application of metallurgical slags
is in building industry, in cement production, building binders, cement containing
mixtures, building products and building materials.
[0027] Basically it concerns these main types of the slags:
- blast-furnace slags from pig iron production
- steel slags from production and refining of steels
- slags of secondary metallurgy from ladle furnaces processes
- slags from production, refining and processing of non-ferrous metals
[0028] The highest volumes of the slags develop in iron and steel production. Here slags
develop basically in the three stages of production - reduction, steel production
and secondary metallurgy (
Sorrentino, F. and Gimenez, M. 11th Inter. Congress on the Chemistry of Cement 2003,
Durban, South Africa, pgs. 2139-2146, 2003). Result of the first stage of reduction is pig iron and blast-furnace slag. Depending
on the manner, in which melted blast-furnace slag is cooled and solidifies, four different
types of slag are produced, granulated, air-cooled, pelleted and expanded. In the
second stage, steel and steel slag is produced from pig iron in oxidizing process
in oxygen converter and in electric arc furnace. In the third stage - secondary metallurgy,
high-grade steels and slags develop from ladle furnace process - ladle slags. Slags
from the second and the third stage are air-cooled only.
[0029] Currently, blast-furnace melted slags are ganulated by wet or semi-wet way (
Demeter P., Mihok L. Baricová D. and Seilerová K., Acta Metallurgica Slovaca, 12,
pgs. 67-75, 2006). In the wet granulation, melted slag is poured out of ladle to water pool, where
the slag is granulated and solidified in the form of separate grains, or is poured
through water jet nozzles in the granulation plant and then the slag falls into water
pool. Their microstructure is in the major part formed by glass. Blast-furnace granulated
slag is in the large volumes used in production of cement and concretes as latent
hydraulic admixture. It is possible to use it also as slag sand.
[0030] Air-cooled blast-furnace slag is formed by pouring of melted slag to the slag pits
with controlled cooling, where it cools at the open air forming crystalline structure
with numerous macropores formed by gases released during cooling. After its solidification,
the slag is extracted from the pits, crushed and sorted to the different fractions.
It is then used as artificial compact aggregates - slag aggregates for building purposes.
It serves as substitute for natural stone aggregates in the production of concrete
for concrete constructions, road constructions, road and wide area stabilizations,
recultivation and so.
[0031] Pelleted slag is formed by spreading of the melted slag over carbon plate (so called
deflector), where a layer of slag is broken to pieces by jet of water, which are thrown
to air by centrifugal force of rotating drum. When pieces of slag come to contact
with the air they gain roundish spherical forms and expand under pressure of gases
closed in the volume under solidified surface. The result of this are porous spherical
pellets, separated regarding to dimensions of particles on the basis of curves of
their flight.
[0032] Expanded slag is formed by pouring of melted blast-furnace slag into the shallow
pits with water jet nozzles provided on their bottom. Water is through nozzles injected
to melted slag, it evaporates and creates bubbles in the solidifying structure of
slag, creating a product with low bulk weight. Solidified porous slag is then extracted,
crushed and separated. Expanded slag is used in building industry as expanded slag
aggregates for production of light-weight concretes.
[0033] By special processes of cooling of the liquid blast-furnace slag also other products
are prepared such as slag wool, felt and foamed slag - pumice. The materials has low
bulk weight, good heat and sound insulating properties, they are thus suitable for
production of various kinds of insulating layers.
[0034] Steel slag is obtained in the process of refining metallic iron in oxygen converter
and electric arc furnace. It contains notable part of refined metallic iron - raw
steel. The steel slag such formed is then separated to two parts, to metallic part
- steel scrap and demetallized slag in the multi-stage process of crushing, grinding
and electromagnetic separation. Steel scrap is recycled by adding to the blast furnace
and steel charge and demetallized steel slag is, after separation, used in the cement
production as raw mixture component - ferrous correction of the cement raw meals,
in the building industry as aggregates for base layers of the roads, railways, wide
areas, dams, for soil stabilization. Its use as the aggregates for concretes for building
constructions and cement-concrete pavements surface covers is prevented by presence
of free lime, which in the presence of humidity hydrates to portlandite Ca(OH)
2 and volume changes by said reaction would destroy the concrete stone and cause destruction
of the entire construction. This drawback can be moderated by natural ageing of the
demetallized steel slag freely at the outside, where comes to interaction of free
lime with air humidity, water coming from rain, snow and ice respectively. This process
can be speed up by ageing with water steam, pressurized water steam, hydrating and
aeration, additives - injecting of quartz sand to already liquid steel slag, where
it binds with contained free lime creating calcium silicates.
[0035] Slags from ladle furnace processes - ladle slags called also calcerous slags, are
obtained in the production of various kinds of steels in ladle furnaces. Various kinds
of steels require different methods of processing, thus creating various kinds of
the ladle slags with different composition and characteristics and regularly with
very low possibility of their exploitation, therefore the majority of them is only
landfilled. Slags contain high portion of free lime, by hydration of which self-degradation
of their structure occurs. Their potential resides in their use as a source of CaO,
SiO
2, Al
2O
3, MgO in the cement raw mixtures.
[0036] The slags from production, refining and processing of non-ferrous metals are obtained
in the processes of coloured metallurgy of such metals as copper, titanium, nickel
etc. These slags are exploitable at most for production of artificial aggregates designed
especially for various base layers and stabilizations. They can be used in cements
production as a flux in the burning of cement clinkers.
[0037] All kinds of metallurgical slags differ from each other by chemical composition and
mineralogical composition. Regarding the chemical composition, they are very different
in content of CaO and Fe
2O
3, FeO respectively and regarding the mineralogical composition they differ in content
of glassy phase and phase composition of crystallized part.
[0038] The use of metallurgical slags in cements, building binders, cement containing mixtures,
building products and building materials is regulated by valid European and national
standards.
[0039] Granulated blast-furnace slag suitable for cements is defined according to European
standard EN 197-1: 2000 and ground granulated blast-furnace slag for use in concrete,
mortars and grout according to European standard EN 15167-1: 2006 as the glassy material
made by rapid cooling of slag melt of suitable composition as obtained by smelting
iron ore in blast furnace and contains at least two thirds by weight of glassy slag
of chemical composition consisting at least of two thirds by weight of the sum of
calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO
2). The reminder must contain aluminum oxide (Al
2O
3) together with small amount of other compounds. The weight ratio (CaO + MgO)/(SiO
2) must be greater than 1.0. Quick cooling includes quick cooling in water (granulation)
and injection through water and air (pelleting).
[0040] The use of granulated blast furnace slag suitable as the component for cements, masonry
and plastering mortars is defined according to EN 413-1: 2004, cements with low hydration
heat release it is defined according to EN 197-1: 2000/A1: 2004, for cements with
very low hydration heat release it is defined according to EN 14216: 2004, for blast-furnace
slag cement with low initial strength it is defined according to EN 197-4: 2004, for
blast-furnace slag sulphate resistant cements it is defined according to STN 72 2103.
[0041] According to EN 206-1: 2000 fine ground granulated blast-furnace slag can be ranked
among admixtures for concrete of type II. - puzzolanic or latent hydraulic addition,
and powdered crystalline slags can be ranked among admixtures of type I. - nearly
inert addition. Admixtures of type II. - fine ground inorganic, puzzolanic, or latent
hydraulic material, are added to concrete to improve certain properties, or to achieve
special properties. Admixtures of type I. serve in concrete more or less as filler.
[0042] According to EN 12620: 2002 slags are classified as artificial aggregates for concrete.
The compact aggregates made of air cooled blast-furnace slag must not present neither
decomposition of calcium silicate nor decomposition of iron, it must be volume stable.
The slags can be used as artificial aggregates also in mortars for masonry, plastering,
floors, leveling, basis, maintenance, grouting, according to EN 13139: 2002, as artificial
aggregates in non-cemented and hydraulic cemented materials used in building industry
and road construction according to EN 13242: 2002. If the expanded slag is used as
light-weight aggregates in light-weight concretes, mortars and grout, its properties
are defined in EN 13055-1: 2002.
[0043] In current antimicrobial cement containing mixtures, ground granulated blast-furnace
slag has been used as latent hydraulic admixture or as filler, disregarding its other
application possibilities. As an example that can be mentioned are, cement mixture
based on calcium aluminate cement, fine ground blast-furnace granulated slag and antibacterial
additive based on Ag
+ and/or Cu
2+ according to
JP 2006327866, cement mixture based on calcium aluminate compounds and colemanite (colemanite mineral
is hydrated calcium triborate Ca[B
3O
4(OH)
3].H
2O), which further comprises one or more kinds of admixtures, of such type as fine
ground blast-furnace granulated slag, fly ash, silica fume and there can also be added
inorganic salts according to
JP 2005139010, antibacterial penetration hardening agent, penetration hardening agent for maintenance
of stone constructions which comprises 1 to 12% of antibacterial organic compounds
and inorganic fillers consisting of pulverized stone powder, particles of water granulated
blast-furnace slag, portland cement, gypsum and inorganic pigments according to
JP 10025175, algae and mould resistant concrete mixture, which is composed of cement, aggregates
and comprises at least one material such as silica fume, fly ash and fine powder of
blast-furnace slag, into which selective organic herbicide and/or inorganic metallic
ion antibacterial agent is added in the amount of 0.3 to 6 kg/m
3 of concrete mixture according to
JP 09002859.
[0044] The invention is characterized in that antimicrobially active agent for building
industry is metallurgical slag.
[0045] The invention is also characterized in method of production of antimicrobially active
agent for building industry, in which metallurgical slags are antimicrobially activated
mechanically and/or chemically.
[0046] The invention is further characterized in use of metallurgical slags as antimicrobially
active agent for building industry.
[0047] The invention does not relate to currently used antimicrobial additives such as common
biocides based on organic compounds and inorganic compounds with content of Ag
+, Cu
2+ and Zn
2+, bioactive glasses, glass-ionomer cements, medicinal cements and pharmaceutical and
disinfecting preparations.
[0048] Antimicrobial activity of metallurgical slags is activated mechanically and/or chemically.
[0049] Mechanical activation is carried out by crushing and/or grinding and/or spreading
and/or separation and/or mixing. The slags are batched either to crushing units in
the process of crushing and/or to grinding units in the process of grinding and/or
to separation units in the process of separation and/or to mixing units in the process
of mixing of either slags as such and/or in the preparation of cements and/or building
binders and/or cement containing mixtures and/or building products and/or building
materials. The slags are activated by mechanical treatment by the change of size of
particles, of granulometry of metallurgical slags, of grain distribution of the particles,
of specific surface, of surface electrostatic charge of particles, of surface tensions,
or of surface energy forces. Number of particles greater than 500 µm, after mechanical
activation, is maximum 99% by weight of overall granulometry.
[0050] Chemical activation is carried out by addition of activators to the slags, such as
inorganic and/or organic compounds, e.g. compounds with bound ions of alkali metals
(Na
+, K
+...) and metals of alkali earths (Ca
2+, Ba
2+...), cement clinkers, cements, additives and admixtures used in cement production,
e.g. grinding aids, setting time regulators, additives used in the production of concretes,
mortars, dry plastering mixtures, e.g. plasticizers, aeration additives, accelerating
additives, inhibiting additives, lime, calcium hydrate, limestone, dolomite, gypsum,
anhydrite, plaster and/or by moistening and/or steaming and/or autoclaving and/or
thermal treatment by drying and/or overheating and/or burning.
[0051] The slags are activated by chemical treatment by either modifying of their chemical
composition and/or their mineralogical composition and/or destruction of slag structure
and/or excitation of hydrating reactions and/or excitation of binding processes and/or
releasing of ions and complex compounds out of the slag structure including heavy
metals and/or by change of pH and/or change of surface charges and forces and/or phase
changes due to hydrating changes and/or phase changes due to thermal changes.
[0052] Antimicrobial active metallurgical slags for building purposes are applied by simply
adding them to desired location and/or by adding them to cements, building binders,
cement containing mixtures, building products and building materials.
[0053] The additions of antimicrobially active metallurgical slags to cements, building
binders, cement containing mixtures, building products and building materials provide
for their antimicrobial resistance.
[0054] The chemical composition of metallurgical slags is very important for the invention,
especially the content of CaO and also mineralogical composition as well. The higher
is ratio of glassy phase, the energetically richer is slag and thus more hydraulic
with higher initial antimicrobial potential. Not all slags are fully suitable, some
with low content of CaO or low content of glassy phase are hardly being activated,
they have low antimicrobial potential after their activation, respectively.
[0055] The blast-furnace granulated and air cooled slags are by the chemical composition
almost identical, but they are diametrically different by the extent of re-crystallization.
Air cooled slag is completely crystallized, granulated one regularly contain more
than 90% by weight of glass. The chemical composition of blast-furnace slags depends
on composition of blast-furnace batches and of course on chemical composition of iron
ores. Blast-furnace slags are created by cooling after tapping of melted batches.
Final blast-furnace slag is composed of oxides and sulfides of elements, which are
not reduced at all in blast-furnace, i.e. CaO, MgO, Al
2O
3, MnO, FeO, FeS, MnS as well as other complex compounds (e.g. silicates, ferrites,
etc.). Chemical composition of major constituents of blast-furnace slags varies in
the range of 30 to 52% by weight CaO, 28 to 43% by weight SiO
2, 5 to 24% by weight Al
2O
3, 0.2 to 3% by weight of ferrous and ferric oxides FeO + Fe
2O
3, 1 to 18% by weight MgO, 0.2 to 3% by weight S
2-, 0.2 to 2% by weight MnO.
[0056] Hydraulic activity of slags is expressed by basic modulus M
H, what is weight ratio of sum of basic oxides to sum of acidic oxides according to
reaction (4). The higher it is, hydraulic more active is the slag in process of hydration.
M
H = (CaO + MgO / (SiO
2 + Al
2O
3) (4)
[0057] Regarding basic modulus, blast-furnace slags are classified as basic M
H > 1, neutral M
H = 1 and acidic M
H < 1. The slag basicity is very important in the melting of blast-furnace batch, because
in order to provide good desulphurizing capacity of the slag it is necessary to obtain
basicity values over 1. Activity of slags is also defined by activity modulus M
A, what is weight ratio of aluminum oxide to silicon dioxide according to equation
(5).
M
A = Al
2O
3 / SiO
2 (5)
[0058] Activity modulus M
A regularly varies in the range 0.1 - 0.5. The higher it is, more active is the slag.
[0059] In the iron production, slag is created by melting of iron ore tailing, slag forming
admixtures and coke ashes. All impurities contained in iron ore (so called tailing
composed of quartz sand, soil, clays, carbonates, sulfur and phosphorus compounds)
and in coke (ashes) end in the slags. The slags contain also parts of refractory materials
melted out from furnace lining. Especially compounds of sulfur and phosphorus negatively
affect quality of pig iron. Because these impurities can, at certain combinations,
raise melting temperature of mixture, what is not economical, corrective slag-forming
admixtures are added to the blast-furnace batch, the most frequently limestone and
dolomite. The composition of slag is therefore properly controlled and is relatively
stable, in order to reach the lowest possible melting temperatures. Melted slag has
lower density 2800 kg/m
3 than pig iron with density of 7000 kg/m
3, therefore melted slag floats on melted iron and can be discharged, tapped separately.
Slag-forming admixtures react with components of tailing and inorganic part of fuel
at temperatures to 1800 °C and produce easy-melting calcium and magnesium silicates
and aluminosilicates. The liquid slag is micro-unregular melt, which is composed of
cations Ca
2+, Mg
2+, Na
+, K
+, Mn
2+, Fe
2+, etc. and anions Si
2O
52-, Si
2O
76- , AlO
69-, PO
43-, SO
42-, S
2-, O
2-, etc., which, during slag cooling, mutually react producing complex chains [-Me-O-Si-]
n (Me is metal ion and n represents chain length) with various length and structure.
When the melt is cooled quickly, the complex ions fail to decompose and to form more
simple and mobile clusters of ions, which could easily diffuse in the melt and become
crystallization nuclei. The melt is by quick cooling undercooled and hardens to the
glass. The slag glass structure is similar to the structure of common glass. It form
three-dimensional lattice, which is filled with complex anions and cations. Amphoteric
elements Al and Fe can, in the glass structure, form groups with acidic feature AlO
45- and FeO
45-, or basic feature AlO
69- and FeO
69-, the glass properties are significantly changing by ratio of groups MeO
69- / MeO
45- . Some slag melts, mainly with high content of SiO
2 and Na
2O are in the process of cooling separated to two liquids, they segregate by separation
of one liquid within the other in the form of small drops, what causes micro-heterogeneity
of glass structure. There are also small crystals, crystallization nuclei as directed
grouping of ions, appearing in the slag glass. The most stable groupings of ions are
Ca
2SiO
4, CaSiO
3, Na
2Si
2O
5, Na
2SiO
3 and other.
[0060] Depending on the way of its cooling various kinds of slags develop. If the slag is
slowly cooled in the open air, air cooled slag is developing. If it is cooled by water
in water pools or by stream of water, granulated slag develops in the form of coarse
sand having yellow-brown even gray colour. Air cooled slags have dark gray colour.
Fast cooling of slag by water, prevents its re-crystallization and slag possesses
glassy character and it can contained up to 30% of water immediately after granulation.
This amount of water changes during storage, handling and transportation of granulated
slag in the form of coarse sand, it drops to values of approx. 10%. If slag is cooled
by water and air in combination in granulating wheel, pelleted slag so develops in
the form of spherical particles with minimal content of water.
[0061] The basic slags crystallize quickly, acidic ones slowly. Slowly cooled basic slags
substantially completely crystallize out. They are formed by conglomerate of various
stable crystalline phases connected with small amount of glassy phase of varying composition.
The acidic slags, even when cooled slowly, crystallize less due to fast growth of
their viscosity. SiO
2 forms very viscous melt. If cooled quickly, slags crystallize out only partially
and they are from 90 to 95% composed of glassy phase. Constituting minerals in the
slowly cooled acidic slags are anortite CAS
2, diopside CMS
2, hedenbergite CaO.FeO.2SiO
2. There are especially gehlenite C
2AS, akermanite C
2MS
2, melilite - solid solution of gehlenite and akermanite, merwinite C
3MS
2, wollastonite β-CS, pseudowollastonite α-CS, belite β-C2S, shanonite γ-C
2S, rankinite C
3S
2, monticellite CMS, calcium aluminates CA, C
12A
7, CA
2, magnesium spinel MA, enstatite MS, forsterite M
2S, present in the neutral and basic slags. Secondary constituents such as Fe
2O
3, MnO, sulfur in amount to 2% compose solid solutions with constituting minerals.
At higher content, magnetite FeO.Fe
2O
3, hematite Fe
2O
3, wüstite FeO, oldhamite CaS, alabandite MnS, pyrhotine FeS, tefroite 2MnO.SiO
2 rodonite MnO.SiO
2, manganous spinel MnO.Al
2O
3 and other can form separate phases. There can occur also perovskite CaO.TiO
2, ilmenite FeO.TiO
2, fluorite CaF
2 and carbides in some slags. During slow cooling of the basic slags occurs so called
silicate decomposition, caused by transformation of β-C
2S to γ-C
2S, which is accompanied by volume growth about 10%. Slag decomposition can occur also
in hydrating of free CaO, so called calcerous decomposition or of free MgO, so called
magnesium decomposition. Manganous sulfide MnS and ferrous sulfide FeS react with
water according to reaction (6).
MnS + 2H
2O → H
2S + Mn(OH)
2 (6)
[0062] The volume of phases developed by the reaction is significantly greater than of initial
constituents, what causes so called manganeseous or ferrous decomposition of slag.
In wet environment, regarding to iron, oxidation can also occur of Fe
2+ to Fe
2+ with development of ferrous sulphate and also ferric sulphate, what is associated
with increase of volume about 40%. The threat of decomposition of granulated slags
resides also in their slow re-crystallization with development of crystals of gehlenite,
akermanite, merwinite and other phases.
[0063] The air cooled blast-furnace slags are identical with granulated blast-furnace slags
by their chemical composition, but very different by their mineralogy, either they
do not contain glassy phase, or contents of this phase is minimal. They are well crystallized
and in regard of mineralogy they are composed of melilite, solid solution of gehlenite
C
2AS and akermanite C
2MS
2, merwinite C
3MS
2, calcium aluminate ferrite C
4AF, quartz SiO
2.
[0064] The steel and ladle slags have completely different chemical as well as mineralogical
composition than the blast-furnace slags. The colour metallurgy slags are completely
different in the chemical and mineralogical composition from said slags from production
and refining of iron and steels.
[0065] The steel slags are richer with FeO, Fe
2O
3 respectively. The chemical composition of major constituents of demetalized steel
slags varies in the range Fe total 17 to 30% by weigh, 24 to 43% by weight of iron
oxides FeO + Fe
2O
3, 40 to 51% by weight of total CaO, free lime CaO 4.5 to 11% by weight, 8 to 17% by
weight of SiO
2, 1 to 8% by weight of Al
2O
3, 1 to 8% by weight of MgO, total sulfur S 0.04 to 0.25% by weight, 1 to 5% by weight
of MnO. The main minerals are wüstite FeO, solid solution of magniesiawüstite (Fe,Mg)O,
dicalcium silicates α'-C
2S and β-C
2S, tricalcium silicate C
3S, free lime CaO, which then hydrates to portlandite Ca(OH)
2 and after carbonation it changes to calcite CaCO
3, calcium ferrites C
2F, CF, CF
2, calcium aluminate ferrite C
4AF, calcium aluminates CA, C
12A
7, C
3A, melilite solid solution of gehlenite C
2AS and akermanite C
2MS
2, merwinite C
3MS
2, hematite α-Fe
2O
3, β- Fe
2O
3, magnetite Fe
3O
4, periclas MgO. Phosphorus is in the slag bound with dicalcium silicate in the form
of solid solution C
2S - C
3P, sulfur as CaS is bound with calcerous ferrite as Ca-S ferrite. The steel slags
are not granulated a they in fact do not contain glassy phase.
[0066] The calcerous ladle slags are rich with CaO with varied chemical composition according
to type of steel, with which they are used, practically in ten main compositions.
They may contain 38 to 60% by weight of CaO, 9 to 32% by weight of SiO
2, 7 to 19% by weight of Al
2O
3, 0.01 to 3% by weight of Fe
2O
3, 0.6 to 9% by weight of FeO, 0.5 to 2% by weight of SO
3, 3.3 to 13% by weight of MgO, 0.1 to 5% by weight of MnO with possible content of
CaF
2 0 to 10% by weight. The calcerous slags contain also ferrous iron in the form of
teardrops, which however, can be separated out. The content of glassy phase depends
on cooling speed, but neither these slags are granulated, therefore its content is
also in this case low. The mineralogical composition of calcerous slags is composed
of larnite β-C
2S, tricalcium aluminate C
3A, gehlenite C
2AS, calcium aluminate ferrite C
4AF, shanonite γ-C
2S, which causes spontaneous decomposition and pulverization, free lime CaO, quartz
SiO
2, metallic iron, gypsum CaSO
4.2H
2O.
[0067] The slags from production, processing and refining of non-ferrous metals are mainly
acidic with raised content of SiO
2 27 to 45% by weight and iron Fe 14 to 32% by weight and small amount of CaO 5 to
23% by weight, the amount of sulfur S ranges between 0.1 to 3% by weight. The main
minerals of these slags are fayalite 2FeO.SiO
2, magnetite Fe
3O
4, anortite CAS
2 and pyroxene group minerals of the type ABT
2O
6 (A - Na
+, Ca
2+, Fe
2+, Mg
2+, Zn
2+, Mn
2+, Li
+; B - Al
3+, Fe
3+, Mg
2+, Mn
2+, Ti
3+, Cr
3+; T - Si
4+, Al
3+). During the fast cooling these slags practically completely turn to glass, which
is hard to grind, during the slow cooling content of glassy phase decreases to 20
to 40% by weight.
[0068] It is advantageous, if the metallurgical slags contain higher amount of fluorides,
or fluorine containing compounds.
[0069] Significant differences in the chemical and mineralogical composition of metallurgical
slags require different approaches to their activation in order to generate their
antimicrobial effects.
[0070] As mentioned, metallurgical slags are activated mechanically and/or chemically, to
obtain antimicrobial effects.
[0071] Mechanical activation includes the change in particle size, change of granulometry
of metallurgical slags, grain distribution of the particles, specific surface, surface
electrostatic charge of particles, surface tensions, surface energy forces.
[0072] During the mechanical activation by comminution it comes to destruction of electrovalent
bonds of type Si-O and to creation of unbalanced primary valence forces of opposite
polarity at both newly formed surfaces of ground particles. Electrostatic charges
exist only on the surface of particles of fine ground slags. Static electric charges
of opposite polarity cause clustering of particles of fine ground slags during grinding
- agglomeration. The surface energy forces are increased in direct proportion to increasing
of surface of ground particles. The agglomeration is greater, the finer are ground
particles, the greater is specific surface of fine ground slags.
[0073] The surface charge of particles of fine ground slags influences viability of microorganisms.
Intensity of the surface charge can be controlled by grinding aids. Grinding aids
are antistatic polar compounds. Regarding its polarity, these compounds preferably
bind with reactive centers of grains surfaces of fine ground slags, which are formed
by destruction of electrovalent bonds during grinding. The grinding aids in this manner
weaken forces of surface tension, which cause agglomeration of ground slag particles.
They thus enlarge active surface of slags also during hydration and thus release of
ions to environment. Released ions also affect viability of microorganisms.
[0074] Also water itself as polar molecule affect surface charge. With regard to the presence
of polar covalent bond H-O, oxygen is more electronegative than hydrogen and has fractional
negative charge, however this effect is low when compared to the grinding aids.
[0075] Chemical activation closely relates to the content of glassy phase, the chemical
and mineralogical composition of metallurgical slags. The granulated blast-furnace
slag with the highest content of glassy phase is used as binding active admixture,
other slags in building mixtures serves rather as inactive space filler in building
product.
[0076] The granulated blast-furnace slag has latent hydraulic properties dependent on its
chemical and phase composition, especially on the content of glassy phase. Its binding
properties can be excited by addition of cement, thus portland cements with granulated
blast-furnace slag as minor additional constituent, portland slag cements, portland
composite cements with granulated blast-furnace slag as main constituent or as minor
additional constituent, blast-furnace cements or composite cements, all cements with
granulated blast-furnace slag as minor additional constituent, respectively, special
cements such as sulphate-resistant, cements having low hydrating heat release, cements
having low initial strength, cements for masonry and plastering mortars with addition
of granulated blast-furnace slag and various cement containing mixtures with addition
of granulated blast-furnace slag are produced. They further can be excited by addition
of gypsum, anhydrite, or plaster - slag-sulphate binders are thus produced, by addition
of air or hydraulic lime or calcium hydrate - slag calcerous binders are thus produced,
or by addition of sodium Na or potassium K hydroxides, carbonates, silicates - binders
based on alkali activated slags or geopolymers binders are thus produced.
[0077] Capability of glassy as well as crystalline slags to react with water, to set and
to harden depends on their extent of crystallization. Completely crystallized blast-furnace
slags react with water very little or not, respectively. When they hydrate, very small
amount only of gelled products is produced, mainly gelled silicic acid. The glassy
slags react with water more actively than crystalline ones. While only few slag minerals
have hydraulic properties in crystalline state, e.g. C
2S, in glassy state majority have them. Glass is metastable phase and in the contact
with water it tends to transform to more stable crystalline phase. High internal energy
of glass provides for its increased solubility in the contact with water. Regarding
hydration of slags the presence of complex anions is very important, and amongst them
the most active monosilicate [SiO
4]
4- and monoaluminate [AlO
4]
5- ions. In relation to pH value various complexes Al(OH)
4-,Al(OH)
52- or Al(OH)
63- are developed. At the beginning of hydration metastable supersaturated solution is
developed, of which later hydration products are being crystallized. Hydration is
carried out topochemically only on surfaces of slag grains. Colloid layers are developed
on hydrating grains, mainly gels of Si(OH)
4 and Al(OH)
3, which hinder inflow of water to non-hydrated surface of grains and ions Ca
2+ are being released to the solution. Hydration rate of glassy slags grows, similarly
as it is with crystallized slags in presence of lime and calcerous sulphates. Acceleration
of the hydration of glassy slag in the presence of basic Ca
2+ ions causes destruction of colloid acidic envelopes of Si(OH)
4 and Al(OH)
3 and creation of the network of capillars through which water has access to non-hydrated
grains. Ca
2+ ions react with Si(OH)
4 and Al(OH)
3 producing primary low-alkaline calcium hydrosilicate C-S-H and calcium hydroaluminate
C-A-H gels. During hydration, exchange of ions of metals (Na
+, K
+, Mg
2+ etc.) for H
+ from water environment takes place, what causes deformation of the slag structure
and acceleration of its dissolving, while the ions of heavy metals are also released
to the solution. The bonds Me-O (Me: Ca, Mg), Si-O-Si, Si-O-Al, Al-O-Al on the surface
of slag grains in the presence of OH
- and electron donoring ions Na
+ and K
+ in strongly alkaline environment are splitted. The bonds Me-O are weaker than Si-O
and Al-O and thus more Ca and Mg is released to the surrounding water environment
than Si and Al, which enrich surface of the hydrating grains of slags. Negative charges
of Si-O
- anions are compensated by present alkali creating bonds Si-O
--Na
+ and thus produced alkaline silicates are able to react with bivalent ions creating
complexes of the type Si-O-Ca-OH. In the presence of ions SO
42- calcium hydrosulfoaluminates ettringite C
3A.3CaSO
4.32H
2O is developed, which after a time is transfered to calcium monosulphate C
3A.CaSO
4.12H
2O. The ions of SO
42- hinder creation of the water impermeable layers of Si(OH)
4 and Al(OH)
3, what improves hydration of the slags. By use of Na
+ or K
+ compounds during excitation of the hydration of slags natrium N-C-H-S or potassium
hydrosilicates K-C-S-H are produced, which gradually re-crystallize to calcium hydrosilicates.
During hydration the local changes of pH occur, therefore the retaining of high value
of pH in solution, which promotes continuation of slag hydration is very important.
Further hydration of slag is then carried out by its direct reaction with water, while
in the majority C-S-H gels with lowered C/S ratio and raised content of Al, hydration
products of the type C
4AH
13, C
2ASH
8, solid solutions of hydrotalcite mineral Mg
6Al
2CO
3(OH)
16.4H
2O and hydrogarnets C
3AS
3-nH
n, C
6AFS
2H
8 and ettringite are produced. The type and chemical composition of hydration products
depend on chemical and mineralogical composition of the slag, on the type of activator,
on specific surface and the method of treatment of the mixture during setting and
hardening. At higher alkali concentration also amorphous compounds of zeolite type
Me
n[-(Si-O
2)
z-Al-O
2-]
n.xH
2O can be formed, which development is promoted by increase of Al/Si ratio and decrease
of Ca/Si ratio.
[0078] The chemical activation promotes release of ions and various complex compounds to
the water environment - water solution. The release of ions and complex compounds
to the surrounding water environment especially close to the surface of particles
grows also with increasing specific surface. In surrounding environment then comes
to changes of pH of water environment. Presence of ions, in water solution affect
also osmosis, i.e. the pressure of ions in solution on cell membrane of microorganisms.
Primary C-S-H gels are metastable. Metastable hydration phases have higher energy,
they tend to transfer to more stable hydration phases, up to crystalline forms and
thus give off energy and affect energetic potential of environment.
[0079] Activated hydrating slag lowers permeability of cement stone. Insoluble colloid compounds
that seal porous system of cement matrix are produced by reaction of soluble alkaline
silicates with calcium hydroxide released during hydration of calcium silicates. From
alkaline sulphates develops calcium sulphate, which by the next reaction forms with
calcium aluminates ettringite, calcium monosulphate respectively. Decreased permeability
of cement stone prevents grow-off of hyphae from mould on the surface to the volume.
Because slags hydrate substantially longer compared to the cements, even after water
supply is interrupted they are able to hydrate after another supply of humidity, i.e.
taking water from the environment, which would be necessary for living of microorganisms.
[0080] Microorganisms require particular optimal conditions of outer environment for their
growth (humidity, nutrients, osmotic pressure, temperature, light, pH of environment
...), in which their growth is maximal.
[0081] Microorganisms grow in pH range of 2.5 to 9 and optimum for various microorganisms
is between pH 5 and 7.5, though exceptions exist. Generally, the majority of bacteria
grow better in neutral and slightly basic environment (pH 7 and slightly over 7),
while majority of fibrous fungi (mould) require acidic environment, i.e. lower than
pH 7. If metallurgical slags are activated, in order to raise pH over 7 in humid environment,
decrease in growth of fungi is thus obtained and pH over 9 also in growth of bacteria
as well. With pH over 9 even -cidal (lethal) effect on microorganisms is attained
by activated metallurgical slags.
[0082] Microbial cells has greater inner concentration of soluble substances than surrounding
water environment and have thus greater osmotic pressure (osmotic pressure - pressure
of ions on cell membrane). While cells are present in environment with equal osmotic
pressure as is inside a cell (isotonic environment), cell normally grows and reproduces.
In environment with osmotic pressure lower than is inside a cell (hypotonic environment)
molecules of water passes from the outside environment to the inside of a cell, with
the aim to decrease pressure of salt ions on inner membrane of a cell. As a result
of this, cell with excess of water could burst. In the case of fungi and majority
of bacteria this excessive passage of water to cells is prevented by relatively strong
cell wall. Fibrous fungi (mould) have only thin wall at the end of hyphae, thus moving
them to environment with very low osmotic pressure (hypotonic environment) can result
in burst of terminal cells and leak of cytoplasm to the environment. On the contrary,
in environment with osmotic pressure higher than in inside of a cell (hypertonic environment),
the cell tends to dilute high concentration of salts out of cell. Water leaves from
the cell to the environment, whereas the cell diminishes, and also in its relatively
strong cell wall. In such environment, regarding minimized chemical activity, microbial
cell only survives, it does not reproduce. It is possible to activate the metallurgical
slags also in this sense of antimicrobial effect against microorganisms according
to present solution.
[0083] The growth of microorganisms can be suppressed not only by change of factors of the
outer environment, but also by release of antimicrobially acting substances from activated
metallurgical slags. These substances inhibit growth and reproduction of cells, while
they can affect their metabolism in various ways (1. inhibit synthesis of cell walls,
2. affect function of cell membranes, 3. inhibit energetic metabolism, 4. act as antimetabolites,
5. inhibit synthesis of nucleic acids, 6. inhibit protein synthesis). The same compound
can affect cell of microorganisms at several locations, however by use of limited
concentration of given substance in water solution, this substance attacks only one
location, which is the most sensitive to its effect.
- 1. Microorganisms and macroorganisms except animals have protective cell surface layer
- cell wall. Individual types of organisms are characterized by specific structure
of cell wall. In the cell wall of all organisms typical constituent is present, which
constitutes macromolecular network and provides cell with its characteristic shape
and rigidity. This molecular network in walls of fungi is composed of chitin, while
in majority of bacteria it is peptidoglycan. Synthesis of peptidoglycan can be intervened
by several substances, which can inhibit (suppress) enzymes of biosynthesis, can bind
to lipid transporters or bind to substrates (initial substances of chemical reactions).
Walls of bacteria and yeast are similar in that, their main constituent is chitin,
which is present mainly in growing tips of hyphae. Some antifungal active substances
inhibit (suppress activity of enzyme) enzyme chitin synthetasy, as a result of what
tips of hyphae swell and burst.
- 2. Cell membranes as composed of two layers of phospholipides, into which bigger or
smaller protein molecules are sunk, which also mutually connect them. Structure of
prokaryotic organisms (bacteria) is quite simple. They have only one cytoplasmic membrane,
on the cell surface, though some bacteria have various folds on the inner side of
membrane. Bacterial cytoplasmic membrane is place of numerous biochemical activities
in cell (breathing, energetic metabolism, excretion of waste substances...). Cell
structure of eukaryotic organisms (yeast, fibrous fungi) is more complex. Cell membrane
is present not only on cell surface, but also on surface of some organelles inside
a cell (mitochondria, chloroplast). Important constituent of eukaryotic membranes
(of yeast, fibrous fungi), by which they essentially differ from prokaryotic, are
sterols. Cytoplasmic membranes are semipermeable, transport of substances through
them is strictly controlled, by what the cell keeps balance and stability of its inner
environment. When cytoplasmic membrane is operating properly the transport of nutritients,
ions, metabolites, through membrane is controlled, but due to effect of some substances,
the membrane looses its controlling ability, what results in collapse of cell.
- 3. Antimicrobially active agents, that damage function of membrane, often have effect
also on energetic metabolism (breathing), because processes of energetic metabolism
are closely related to cell membranes. In prokaryotic cells (bacteria) reactions of
energetic metabolism (breathing) are carried out in folds of inner side of cytoplasmic
membrane, while in eukaryotic cells (yeast, fibrous fungi) these processes are carried
out in mitochondria and chloroplast, which also are enveloped by cell membrane.
- 4. Many antimicrobial active agents including substances from activated metallurgical
slags resemble by their structure primary metabolites (primary metabolites - substances
that are formed during normal cell metabolism and subsequently enter further biochemical
processes in cell) and can enter in the form of antimetabolites (substances that a
cell is not able to include in its metabolism, however they resemble by their structure
primary metabolites) as their inhibitors. This results in the production of defective
product of biochemical reaction, whereas normal function of a cell is disturbed, as
a result of what is its death. Typical antimetabolites of amino acids (constituents
of proteins), purines (constituents of nucleic acids), pyrimidine (consituents of
nucleic acids), and vitamins (substances necessary for normal function of enzymes).
- 5. Antimicrobially active agents that inhibit (suppress) biosynthesis of nucleic acids
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), can intervene these processes
at various levels. The first level is metabolism of nucleotides, which are precursors
(building components) of nucleic acids. They can inhibit nucleotide synthesis itself,
or directly build-in instead of analogical nucleosides (building constituents of nucleic
acids) to DNA or RNA, thus producing biochemically inactive nucleic acids.
The second level of interventions is polymerization of nucleic acids itself (creation
of copies). Antimicrobially active agents bind with DNA, create complexes with it
and prevent its functions in polymerization reactions.
- 6. Biosynthesis of proteins (protein synthesis) in cells is complex process. Protein
synthesis inhibitors can inhibit (suppress) prokaryotic (in bacteria), eukaryotic
(yeast, fibrous fungi) or both systems at once. Protein synthesis is carried out in
three phases: initialization (beginning), propagation (continuing) and termination
(ending), whereas intervention at each phase has fatal consequences for a cell. Localization
of intervention depends on intensity of activation of metallurgical slags.
[0084] High concentrations of ions and complex compounds released from antimicrobially activated
metallurgical slags act on microbial cell in inhibiting manner, affecting vital functions.
They inhibit transport of electrons during breathing that occurs in membrane of bacteria
and mitochondria (organelles in eukaryotic cells) of yeast and mould.
[0085] Antibacterially active agents from antimicrobially activated metallurgical slags
intervene cells of bacteria and fungi in various ways. Toxicity for microbial cells
is indicated even at very low concentrations. Activity of ions and complex compounds
depends on temperature and pH of the environment. Ions and complex compounds inhibit
activity of number of enzymes, react with electron donor groups, side chains of amino
acids, carboxyl groups (-COOH) and thio-groups (-SH) of proteins, inhibit respiratory
processes (breathing), prevent untwisting of double helix of DNA (deoxyribonucleic
acid). Many enzymes are necessary for energy production of a cell, but when they are
denatured by ions and complex compounds from activated metallurgical slags, they are
not able to provide given function.
[0086] The ions and complex compounds from antimicrobially activated metallurgical slags
have chemiosmotic effect, they interact with proteins and probably also with phospholipides,
which serve as proton pumps in cell membranes. Micromolar concentrations of ions from
activated metallurgical slags on the surface of cell membrane create total destruction
of ΔpH and potential gradient (ΔΨ). They cause collapse of proton gradient in the
membranes, thus causing failures of cell metabolism (chemical reactions in cell) and
subsequently death of cell.
[0087] The ions and complex compounds from antimicrobially activated metallurgical slags
thus have not only one mechanism of action. Mechanism depends on concentration of
ions and complex compounds from activated metallurgical slags in the environment and
on cell response to them.
[0088] inhibiting effect of ions and complex compounds from antimicrobially activated metallurgical
slags is caused by oxidation of thio-groups (-SH) of amino acids.
[0089] The ions and complex compounds from antimicrobially activated metallurgical slags
are able to bind by strong and stable bond to biomolecules such as proteins and enzymes.
These ions react with thio-groups (-SH) of cysteine (amino acid) and atoms of sulfur
(-SCH
3) in methionine (amino acid). Such metal-amino acids can be then built-in to proteins
and enzymes in organism, while damaged and non-functional forms of enzymes are produced.
[0090] In order to have antimicrobially activated metallurgical slags antimicrobially active
in various kinds of cements, building binders, cement containing mixtures, building
products and building materials, they must be present in particular concentrations.
Contrary to common commercial biocide additives, which active concentrations ranges,
on the order, in tenths to oneths % by weight, antimicrobially activated metallurgical
slags concentrations are given in, on the order, tens of % by weight. Minimal inhibiting
concentration of substance (MIC) is a concentration that inhibit (suppress) growth
of microorganisms for 100 %. Growth of microorganisms is 100% inhibited, but microorganisms
are able to survive at this concentration. Minimal microbicidal concentration of substance
(MMC) is concentration that has cidal effect on microorganisms (kills them). Regarding
effects and concentration of biocidal additives, they have different effects on microorganisms.
Microbistatic effect refers to that particular substance in particular concentration
inhibits growth of microorganisms (without closer specification) for 100 %, whereas
it does not kill them, but material is not invaded by microorganisms. Microbicidal
effect refers to that particular substance in particular concentration inhibits growth
of microorganisms (without closer specification) for 100 %, whereas it kills them.
Bacteristatic effect refers to that particular substance in particular concentration
inhibits growth of bacteria for 100 %, whereas it does not kill them, but material
is not invaded by microorganisms. Bactericidal effect refers to that particular substance
in particular concentration inhibits growth of microorganisms for 100 %, whereas it
kills them. Fungistatic effect refers to that particular substance in particular concentration
inhibits growth of fungi for 100 %, whereas it does not kill them, but material is
not invaded by fungi. Fungicidal effect refers to that particular substance in particular
concentration inhibits growth of fungi for 100 %, whereas it kills them.
[0091] Mould resistance of building materials and products is tested according to standard

SN 72 4310: 1977. Mould resistance rate is expressed on the basis of evaluation scale
introduced in table No. 1.
[0092] Table No. 1; Evaluation scale of mould resistance rate of building materials and products according
to

SN 72 4310: 1977
Mould growth rate |
Description |
0 |
Mould is not growing |
1 |
Growth is subtle (scattered colonies of mould) |
2 |
Growth is moderate (numerous small fungi colonies or intact light growth, which covers
less than 25% of sample surface) |
3 |
Growth is intense (growth of mould covers up to 50% of sample surface) |
4 |
Growth is very intense (growth of mould covers up to 75% of sample surface) |
5 |
Growth of mould is complete (growth of mould covers 100% of sample surface) |
[0093] Different chemical and mineralogical compositions of metallurgical slags require
different form of antimicrobial generation and subsequently different forms of application,
while the most used type of metallurgical slags in building industry today is granulated
blast-furnace slag.
[0094] Activated granulated blast-furnace slag with antimicrobial properties as latent hydraulic
admixture is suitable for production of portland cements with granulated blast-furnace
slag as minor additional constituent, portland slag cement, portland composite cements
with granulated blast-furnace slag as a main component, blast-furnace cements, composite
cements and all cements with granulated blast-furnace slag as minor additional constituent,
special cements such as sulphur-resistant, cements with low hydration heat release,
cements with low initial strength, cements for masonry and plastering mortars with
addition of granulated blast-furnace slag, road cements, cements for cement-concrete
pavements covering layers and various cement containing mixtures with addition of
granulated blast-furnace slag. The ratio of granulated blast-furnace slag in cements
can vary in range of 0.01 to 95 % by weight to amount of portland clinker, regarding
type of cement, while this range includes use of granulated blast-furnace slag either
as main component or supplemental and/or special component.
[0095] Cement containing mixtures and building materials are regular concrete mixtures,
concrete mixtures for production of shaped blocks and prefabricates, concrete mixtures
for cement-concrete covering layers of roads and pavement, tunnels, bridges, viaducts,
cement containing mixtures for stabilizing base layers, cement reinforced aggregates,
concretes for massive and big volume buildings, shotcretes, concretes on floors, cement
glues for floor and wall tiles, cement glues for heat insulation systems, heat insulating
mortars, water insulating mixtures, joint-filler compounds, mortars for masonry, mortars
for plastering, finishing plasters, stucco, dry plastering mortars, leveling compounds,
grouting mixtures, sealing suspensions, mixtures for maintenance and repairing of
concrete constructions, maintenance mixtures, mixtures based on aluminate cement and
other special types of cements and binders and so.
[0096] Building binders and special cements can be composed besides binders based on portland
clinker also of binders such as aluminate cements based on calcium aluminates, refractory
cements based on calcium aluminates and other phases, belite cements based on raised
content of C
2S, sulfoaluminate belite cements based on phases 3CA.CaSO
4 and C
2S, white cements, color cements, hydrophobic cements, cements based on alkali activated
slags, geopolymer binders, slag-sulphate and slag-calcerous binders, roman cement,
hydraulic limes, binders with addition of air lime or lime hydrates, calcium sulphate
binders, gypsum binders, anhydrite binders, magnesium binders and others.
[0097] Building products are commonly commercially available building products used at locations
with potential occurrence of microorganisms such as e.g. siding boards, boards based
on cement and wooden wool, wood fibers, concrete blocks based on cement and wood chips,
supporting members, ceiling members, structural members, panels, and so.
[0098] Besides activated granulated blast-furnace slag with antimicrobial effects also all
other activated metallurgical slags with antimicrobial effects can be used in cements,
building binders, cement containing mixtures, building products and building materials,
such as air cooled blast-furnace slags, steel slags, ladle - calcerous slags, or slags
scraped in production, processing and refining of non-ferrous metals. These activated
slags with antimicrobial effects in particular composites can form either coarse aggregates
and/or fine aggregates and/or small aggregates and/or sand fraction and/or aggregates
sand (crush aggregates) and/or sand and/or fine particles and/or fine grains and/or
filler and/or stone powder and/or microparticles and/or nanoparticles and/or pigments
and/or carriers of other substrates and/or fractions modifying mixability and/or fractions
modifying some properties of cement containing mixtures and/or recycled aggregates.
[0099] All types of activated metallurgical slags with antimicrobial properties can be used
in cements, buliding binders, cement containing mixtures, building products and building
materials either separately or as a mixture of slags in amount of 0.01 to 99.99 %
by weight for particular composite. Mixture of slags can contain either two or more
or all types of slags, respectively, in desired proportions, while binary mixture
can contain one of the slags in the amount from minimal to maximal concentration in
the mixture, i.e. 0.01 to 99.99 % by weight and this rule is valid also for multicomponent
mixtures, while each slag can be represented in the amount from minimal to maximal
concentration in the mixture.
[0100] With increasing content of antimicrobially activated metallurgical slag, slags respectively,
in cements, building binders, cement containing mixtures, building products and building
materials, antimicrobial activity against microorganisms is growing as well.
[0101] Antimicrobially active metallurgical slags decrease total costs for creating antimicrobially
clean environment. In combination with cements, building binders, cement containing
mixtures, building products and materials they are exceptionally suitable especially
for construction of new buildings, when still moist unset mortars in closed space
tend to get mould. They are suitable as well as for reconstruction of buildings, flats,
maintenance of microbiologically damaged places.
[0102] Antimicrobial effects of activated metallurgical slags are with this solution substantially
longer-time than it is with regular biocidal preparations. However, antimicrobial
effects of activated metallurgical slags in the mixtures with cements, building binders,
cement containing mixtures, building products and building materials decrease over
time, what depends on aging of hydrating building binder, re-crystallization of hydration
phases and inclusion of active antimicrobial particles of antimicrobially activated
metallurgical slags to hydration phases of hydrating stone of the binder.
Description of embodiments of the invention
Example 1
[0103] Firstly, antimicrobial activity of samples of individual slags on selected representatives
of biodeteriogenic microflora was determined. Antimicrobial activity was determined
on samples of slags 1. - blast-furnace granulated slag VGT, 2. - blast-furnace air
cooled slag VCHT, 3. - demetallized steel slag DOT, 4. - ladle calcerous slag VAP,
5. - slag from copper refining CuT Slags were activated by grinding to specific surface
400 m
2/kg, without use of grinding aids. Chemical composition of individual slags is introduced
in table No. 1 and mineralogical composition in table No. 2. Blast-furnace slag comprised
glassy phase, over 90 % by weight and high content of glassy phase, over 60 % by weight
was also in slag from copper refining, blast-furnace air cooled slag, steel and calcerous
ladle slag were in fact without glassy phase.
Table No. 2; Chemical composition of individual slags in weight units.
Type of slag |
|
VGT |
VCHT |
DOT |
VAP |
CuT |
Slag No. |
Unit |
1. |
2. |
3. |
4. |
5. |
Ign. loss |
[%] |
0,95 |
0,09 |
6,02 |
5,32 |
+ 4,30 |
SiO2 |
[%] |
42,17 |
40,57 |
12,81 |
13,97 |
27,26 |
Al2O3 |
[%] |
6,87 |
8,12 |
1,64 |
17,77 |
7,01 |
Fe2O3 |
[%] |
0,32 |
2,81 |
29,78 |
1,90 |
46,64 |
CaO |
[%] |
41,92 |
41,73 |
52,30 |
58,97 |
7,48 |
TiO2 |
[%] |
0,42 |
0,11 |
0,34 |
0,14 |
0,21 |
MgO |
[%] |
10,39 |
8,44 |
2,54 |
3,30 |
1,90 |
K2O |
[%] |
0,60 |
0,72 |
0,04 |
0,06 |
0,40 |
Na2O |
[%] |
0,17 |
0,19 |
0,07 |
0,07 |
1,07 |
SO3 |
[%] |
1,84 |
2,39 |
0,28 |
1,98 |
0,15 |
MnO |
[%] |
0,68 |
2,31 |
3,54 |
0,38 |
0,61 |
P2O5 |
[%] |
0,05 |
0,14 |
0,48 |
0,05 |
1,26 |
Cl |
[%] |
0,01732 |
0,01115 |
0,01375 |
0,0017 |
0,0012 |
V |
[ppm] |
27,0 |
32,0 |
298 |
54,0 |
41,0 |
Cr |
[ppm] |
69,6 |
65,0 |
981,0 |
419,0 |
5740,0 |
Co |
[ppm] |
21,1 |
21,5 |
98 |
37,6 |
307,0 |
Ni |
[ppm] |
1,9 |
3,4 |
9,9 |
9,8 |
1893,0 |
Cu |
[ppm] |
1,2 |
1,5 |
10,1 |
4,9 |
7273,0 |
Zn |
[ppm] |
98,1 |
18,7 |
41,3 |
12,3 |
50 341 |
As |
[ppm] |
0,7 |
1,4 |
3,2 |
22,1 |
66,65 |
Cd |
[ppm] |
11,6 |
12,0 |
24,3 |
22,0 |
5,0 |
Sb |
[ppm] |
1,5 |
1,8 |
2,0 |
26,7 |
50,2 |
Hg |
[ppm] |
2,9 |
1,9 |
6,6 |
4,2 |
28,5 |
TI |
[ppm] |
1,5 |
3,3 |
5,6 |
6,0 |
19,0 |
Pb |
[ppm] |
4,0 |
17,6 |
3,2 |
7,5 |
9203,3 |
Table No. 3; Identified mineralogical composition of slags
1. |
melilite - solid solution of gehlenite C2AS and akermanite C2MS2 |
2. |
melilite - solid solution of gehlenite C2AS and akermanite C2MS2, C4AF, quartz SiO2 |
3. |
wüstite FeO, C4AF, free lime CaO, portlandite Ca(OH)2, β-C2S, quartz SiO2 |
4. |
free lime CaO, β-C2S, shanonite γ-C2S, gehlenite C2AS, C3A, CaSO4.2H2O, quartz SiO2 |
5. |
fayalite 2FeO.SiO2, anortite CAS2, pyroxene type CaAlAlO6 |
[0104] Following Bacteria were used as model microorganisms: (G
+) - Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, (G
-) - Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Yeast: Candida
albicans, Rhodotorula glutiniss, Microscopic mycellious fungi: Aspergillus niger,
Penicillium funiculosum, Chaetomium globosum, Alternaria alternata, Trichoderma viride,
Caldosporium herbarum.
[0105] Antimicrobial activity of tested materials was observed on representatives of bacteria,
yeast, and fibrous fungi, with object to obtain more complex view to effect of tested
materials.
[0106] As nutritive media, meat-peptone bouillon for inoculation of bacteria, meat-peptone
agar for cultivation of bacteria, Sabouraud glucose bouillon for inoculation of yeast
and malt agar for cultivation of yeast and mycelial fungi were used.
[0107] For diluting of inoculum of bacteria and yeast physiologic solution was used, for
preparation of sporeceous inoculum solution of Tween 80 was used.
Test conditions
[0108]
- number of tested samples: 5
- incubator temperature: bacteria 30 °C, yeast 28 °C, fibrous fungi 25 °C
- incubator relative humidity: 95%
[0109] Test procedure: Antimicrobial activity was determined by dilution methods in hardened nutritive media
so that resulting concentration of tested substances in nutritive media would be 10,
20, 40 and 60%. pH of nutritive media with addition of slags was strongly basic (pH
11), thus half of samples of each slag was tested at this pH, and the second half
of samples was tested at modified pH (bacteria pH 7.2, yeast and fibrous fungi pH
6.6). The first half of samples with original pH represented real conditions for growth
of microorganisms in cement, the second half of the samples with modified pH represented
ideal conditions for growth of microorganisms. Intensity of growth of microorganisms
was compared to growth in reference nutritive medium without presence of inhibiting
substance. In the case that growth of model microorganisms in presence of slags was
not observed, disc with inoculum was transferred to fresh nutritive medium. After
96-hour incubation effect of slags was inspected: microbistatic (microorganisms are
growing) and microbicidal (lethal) (microorganisms are not growing).
[0110] Test results: The highest antibacterial activity had calcerous ladle slag (4), which intensely
inhibited growth of G
+ and also G
- bacteria, what showed also with the lowest concentration of slag (10%) in nutritive
media. 100% inhibition of growth of some bacteria was observed only in samples of
slags 4, 3 and 2 in concentrations 20% - 60% of slag. Antibacterial activity of slag
samples was decreasing in order: 4 > 3>2>1>5.
[0111] Growth of all model yeasts was 100% inhibited at as low concentration as 20% of slag
1 (blast-furnace granulated slag VGT) and 3 (demetallized steel slag DOT), and 10%
of slag 4 (calcerous ladle slag). Antiyeast activity of slags was decreasing in order:
4 > 1 = 3 > 2 > 5.
[0112] Used model fibrous fungi were sensitive to presence of slag samples in various ways.
As it is apparent from results of inhibition, all slags inhibited growth of fibrous
fungi in concentration 60 % by weight, growth of fungi 100% - 50% inhibited. The most
sensitive to presence of all slags were responding fibrous fungi
Aspergillus niger and
Trichoderma viride, the growth of which in concentrations 20% - 60% of all slag samples, was inhibited
on 100% with static effect (they stopped growth of fungi), and in concentration 60%
by weight of slag 4 (calcerous ladle slag VAP) with -cide effect (killed fungi). The
most resistant fibrous fungus was
Alternaria alternata. Its growth was the most intensely inhibited by slag 4 (calcerous ladle slag VAP),
100% inhibition was observed at 40% - 60% by weight of slag, with static effect. The
most inhibiting activity for all fungi was disposed by slag 4 (calcerous ladle slag
VAP), which 100% inhibited growth of almost all model fibrous fungi in concentrations
20% - 60%, with static effect.
[0113] Regarding that model fibrous fungi were selectively sensitive to presence of tested
slags, it is possible to determine only approximate order of inhibition effectiveness
of slags to fibrous micromycetes: 4 > 1 = 3 > 2 = 5.
pH values of nutritive media did not significantly influence intensity of inhibition
of growth of model microorganisms.
Example 2
[0114] The tests of mechanically activated fine ground blast-furnace slag with specific
surface 440 m
2.kg
-1.
[0115] Tested sample: fine ground granulated slag with specific surface 440 m
2.kg
-1 in mixtures with cement CEM I 42.5 N in concentrations 80 % by weight (what corresponds
to blast-furnace cement CEM III/B 32.5 N according to standard EN 197-1: 2000), 40
% by weight (what corresponds to blast-furnace cement CEM III/A 32.5 N according to
standard EN 197-1: 2000), 20 % by weight (what corresponds to portland slag cement
CEM II/A-S 32.5 R according to standard EN 197-1: 2000) and 10 % by weight (what corresponds
to portland slag cement CEM II/A-S 32.5 R according to standard EN 197-1: 2000).
[0116] Following Bacteria were used as model microorganisms: (G
+) - Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, (G
-) - Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Yeast: Candida
albicans, Rhodotorula glutiniss, Microscopis mycellious fungi: Aspergillus niger,
Penicillium funiculosum, Chaetomium globosum, Alternaria alternata, Trichoderma viride,
Caldosporium herbarum.
[0117] Despite that especially significant in building industry is resistance of materials
to mould, antimicrobial activity was observed also on representatives of bacteria
and yeast, in order to obtain more complex view on effect of tested materials.
[0118] Following nutritive media were used for cultivation: meat-peptone bouillon (cultivation
of bacteria), meat-peptone agar (cultivation of bacteria), Sabouraud glucose bouillon
(cultivation of yeast), malt agar (cultivation of yeast and mycelial fungi), Czapek-Dox
bouillon (inoculation of bricks surface by biodeteriogenes). Following auxiliary solutions
were used: physiologic solution, Tween 80 solution, solution of mineral elements.
[0119] Test procedure: Antimicrobial activity was determined by two different methods:
Method 1
[0120] In this method, antimicrobial activity of slag was determined by dilution methods
in hardened nutritive media so, that resulting concentration of tested substance in
nutritive media would be 10, 20 and 40 %. pH of nutritive media with addition of slag
was strongly basic (pH 10 to 11), thus half of slag samples was tested at this pH,
and the second half of samples at modified pH (bacteria pH 7.2, yeast and fibrous
fungi pH 6.6). The first half of samples with original pH represented real conditions
for growth of microorganisms in cement, the second half of samples with modified pH
represented ideal conditions for growth of microorganisms. In the case, that growth
of model microorganisms in presence of slags was not observed even after 14 days,
disc with inoculum was transported to fresh nutritive medium. After 96-hour incubation,
effect of slags was inspected: microstatic (microorganisms are growing) and microcidal
(lethal) (microorganisms are not growing). Incubator temperature was 30 °C for bacteria,
and 25 to 28 °C for yeast and fibrous fungi, incubator relative humidity was 95%.
[0121] Intensity of growth of microorganisms was compared to growth on reference nutritive
medium without presence of inhibiting substance.
Method 2
[0122] Concrete bricks were prepared, inoculated by mixed biodeteriogenic microflora and
incubated according to procedures stated in ON 72 2127 "Fungistatické maltoviny" (Fungistatic
mortars) and

SN 72 4310 "Zkouseni odolnosti stavebních výrobků a materiálů proti plísním" (Testing
of resistance of building products and materials against mould). In connection with
verification of antimicrobial activity of fine ground granulated slag with specific
surface 440 m
2.kg
-1, aliquot part of portland cemet CEM I 42.5 N was during preparation of concrete bricks,
replaced by slag in weight ratio 80% of slag : 20% of cement, 40% of slag : 60% of
cement, 20% of slag : 80% of cement, 10% of slag : 90% of cement. Bricks with 100%
of cement were used as reference sample. Growth of microorganisms was observed on
original concrete bricks with pH not modified (pH 10 to 11), also on bricks neutralized,
by boiling in distilled water with addition of HCl, on phenolphtalein to neutral reaction.
The first half of samples with original pH represented real conditions for growth
of microorganisms in cement, the second half of samples with modified pH represented
ideal conditions for growth of microorganisms. Inoculated concrete bricks were incubated
according to

SN 72 4310, for 4 months. Bricks on which growth of microorganisms was not observed
nor after 4 months, were after 4-month incubation lied on surface of fresh malt agar
(imprint of brick on nutritive medium) for 30 minutes with an object to discover whether
biodeteriogenic microflora does not loose its viability on the surface of concrete
bricks.
[0123] Intensity of growth of microorganisms was evaluated according to

SN 72 4310.
[0124] Test results: Antimicrobial activity of fine granulated slag with specific surface 400 m
2kg
-1 was tested under conditions
in vitro on the model representatives of bacteria (= prokaryotic microorganisms, i.e. microorganisms
with simple cell structure) and fungi (= eukaryotic microorganisms, i.e. microorganisms
with complex cell structure), while selected types of one-cell fungi (yeast) and multi-cell
fungi (microscopic fibrous fungi) was used.
[0125] It is apparent from obtained results, that tested sample, in long-term, did not significantly
affected growth of model bacteria. Intense inhibition of growth of gram-positive as
well gram-negative bacteria on Method 1 (dilution method), was observed only in concentration
40% of granulated slag, and at pH 7.2 as well as pH10, while after 14 days inhibition
of growth was 100%.
[0126] Growth of model yeast (one-cell fungi) in dilution testing method (Method 1) in the
presence of granulated slag, was not significantly inhibited in long-term, tested
substances cause only delayed growth of yeast. Significant inhibiting effect on growth
of model yeast was observed only with granulated slag in concentration 40% at pH 6.6,
when after 14 days no growth was observed, thus inhibition of growth of yeast was
100%.
[0127] It is apparent from obtained results that granulated slag has significant selective
toxicity against microscopic fibrous fungi, whereas some fibrous micromycetes were
sensitive more, some were sensitive less to presence of granulated slag in nutritive
medium.
[0128] In a view of practical application interesting results were discovered during observing
intensity of growth of biodeteriogenes (bacteria, yeast, fibrous fungi) on the surface
of concrete bricks (Method 2) lied on surface of malt agar or above surface of distilled
water. During 2-monts, 4-month, respectively, incubation of concrete bricks inoculated
by suspension of biodeteriogenes either no growth of microorganisms on the surface
of bricks with granulated slag was observed, or only occasional occurrence of microcolonies
was observed. This phenomenon was observed with bricks lied on surface of malt agar
as well as with bricks lied above the surface of distilled water, and this as well
at basic and also neutral pH of concrete bricks.
[0129] The only one exception were samples containing the highest possible proportion of
granulated slag (slag 80%, cement 20%), with bricks lied on the surface of malt agar.
With these samples, growth of bacteria and yeast on the surface of concrete bricks
was observed, independent of pH. Observation, that they were just bacteria and yeast
growing on the surface of said bricks, was corresponding to previous results of cultivation
(Method 1), in which almost selective toxicity of granulated slag on fibrous micromycetes
was observed.
[0130] In evaluation of growth of selected biodeteriogenes on the surface of concrete bricks
with granulated slag, even reduction of growth of biodeteriogenes when compared to
the reference, was observed, and this with all tested ratios of granulated slag and
cement, except sample - slag 80% : cement 20%.
[0131] It was discovered, when observing imprints of bricks on nutritive medium, that part
of biodeteriogenic microflora has not loosed its viability on concrete bricks even
after 4-month incubation.
[0132] It is possible to state, based on the obtained results, that antimicrobial effect
of granulated slag, added in suitable proportion to cement has positive influence
on long-term protection of concrete against biodeteriogenic microflora, at basic and
also neutral pH.
Example 3
[0133] Blast-furnace slag CEM III/B 32.5 N was prepared according to standard EN 197-1:
2000, by mixing of mechanically activated - ground granulated blast-furnace slag in
amount of 75% by weight to portland clinker, which was pre-ground with setting regulator
- gypsum. Portland clinker and gypsum started, after adding of mixing water, chemical
activation of mechanically activated granulated blast-furnace slag. Cement was used
for production of concrete of strength class C 12/15 with compact aggregates from
mechanically activated - crushed and subsequently to fractions separated metallurgical
slag from refining of copper Cu, which was applied to stabilizing base layer of newly
built landfilling site. Resistance of concrete C 12/15 against mould was tested according
to standard

SN 72 4310: 1977. Based on the results of tests, said building materials can be assigned
mould growth rate 0 and cement CEM III/B 32.5 N, concrete C 12/15 made of it, respectively,
can be evaluated as fungistatic.
Example 4
[0134] Blast-furnace cement with low hydration heat CEM III/C 32.5 N was prepared according
to EN 197-1: 2000/A1: 2004, by mixing of mechanically activated - ground granulated
blast-furnace slag in amount of 85% by weight to portland clinker, which was pre-ground
with setting regulator - gypsum. Portland clinker and gypsum started, after adding
of mixing water, chemical activation of mechanically activated granulated blast-furnace
slag. Cement was used for production of concrete of strength class C 16/20 with compact
aggregates from mechanically activated - crushed and subsequently to fractions separated
steel slag, which was applied to concreting of dam body of the water plant. Resistance
of concrete C 16/20 against mould was tested according to standard

SN 72 4310: 1977. Based on the results of tests, said building materials can be assigned
mould growth rate 0 and cement CEM III/C 32.5 N, concrete C 16/20 made of it, respectively,
can be evaluated as fungistatic.
Example 5
[0135] Cement for masonry and plastering mortars MC 12.5 X was prepared according to standard
EN 413-1: 2004 by mixing of mechanically and chemically activated calcerous ladle
slag regularly used for production of raw mixture for burning of portland clinker,
in amount of 25 % by weight to cement for masonry and plastering mortars and 15 %
by weight of mechanically and chemically activated granulated blast-furnace slag.
From said cement the masonry and plastering mortar was prepared with sand from mechanically
activated - crushed and ground air cooled blast-furnace slag, which was applied in
masonry and plastering of newly built house. Resistance of mortar against mould was
tested according to standard

SN 72 4310: 1977. Based on the results of tests, said building materials can be assigned
mould growth rate 0 and cement for masonry and plastering mortars MC 12.5 X, mortar
made of it, respectively, can be evaluated as fungistatic.
Example 6
[0136] Dry plastering mixture for inner stucco plaster for creation of fine felted pattern
of interior top plaster was prepared with directional prescription:
Wind-blown quartz sand 0-0.6 mm |
800 kg |
CEM II/B-S 32.5 R |
40 kg |
Lime hydrate |
190 kg |
Plasticizer and dispersion agent |
0.5 kg |
[0137] Whereas, cement CEM II/B-S 32.5 R comprised 35 % by weight of ground chemically activated
granulated blast-furnace slag and 1/3 of lime hydrate was replaced by hydrated calcerous
ladle slag. Mixture designed for inner stucco plaster was applied for maintenance
of old mould invaded inner plaster in historical building. Resistance of mixture for
inner stucco plaster against mould was tested according to standard

SN 72 4310: 1977. Based on the results of tests, said building material can be assigned
mould growth rate 0 and mixture for inner stucco plaster can be evaluated as fungistatic.
Example 7
[0138] Dry plastering mixture for joint-filling compound, which can be used for filling
of joints of floor and wall tiles in interior or exterior, was prepared with directional
prescription:
Sand from air cooled blast-furnace slag to 0.25 mm |
500 kg |
Cem II/B-S 32.5 R |
110 kg |
Cem II/A-S 42.5 R |
400 kg |
Powder pigment from slag from copper refining |
10 kg |
Plasticizer and dispersion agent |
25 kg |
[0139] Sand from air cooled blast-furnace slag was activated mechanically by grinding under
0.25 mm and chemically by addition of 8 % by weight of water glass Na
2SiO
3, cement CEM II/A-S 42.5 R comprised 20 % by weight of ground mechanically activated
granulated blast-furnace slag and CEM II/B-S 32.5 R comprised 35 % by weight of ground
mechanically activated granulated blast-furnace slag. Mechanically activated slag
from copper refining was used as powder pigment. Joint-filling compound was applied
in building of cook-house rooms. Resistance of joint-filling compound against mould
was tested according to standard

SN 72 4310: 1977. Based on the results of tests, said building material can be assigned
mould growth rate 0 and joint-filling compound can be evaluated as fungistatic.
Example 8
Testing of resistance of building products and materials against mould
[0140] Determined according to

SN 72 4310.
[0141] Mixture of mould
Aspergillus niger (CCM 8155),
Chaetomium globosum (CCM 8156),
Penicillinum funiculosum (CCM F-161),
Paecilomyces variotii (CCM F-556) and
Gliocladium virens (CCM 8042) - cultures supplied form Czech collection of microorganisms.
Test conditions:
[0142]
- number of tested samples: |
9 |
- sample size: |
⊘ 5.5 cm |
- incubator temperature: |
28±1 °C |
- incubator relative humidity: |
95% |
- time of incubation: |
3 months |
Result: Evaluation of sample by rate according to Table No. 1
[0143]
Mould growth rate |
Description |
0 |
Mould is not growing |
1 |
Growth is subtle (scattered colonies of mould) |
2 |
Growth is moderate (numerous small fungi colonies or intact light growth, which covers
less than 25% of sample surface |
3 |
Growth is intense (growth of mould covers up to 50% of sample surface |
4 |
Growth is very intense (growth of mould covers up to 75% of sample surface) |
5 |
Growth of mould is complete (growth of mould covers 100% of sample surface) |
Results of tests:
[0145] It can be read from the results, that the higher will be proportion of fine ground
granulated blast-furnace slag antimicrobially mechanically activated, antimicrobially
the more effective will be particular, cement containing mixture. Mixtures CEM I 42.5
N (40% T) and CEM I 42.5 N (60% T) correspond to blast-furnace cement of class CEM
III/A 32.5 N, and mixture CEM I 42.5 N (95% T) corresponds to blast-furnace cement
of class CEM III/C 32.5 N according to standard EN 197-1: 2000. Blast-furnace cements
of class CEM III/B 32.5 N (content of granulated blast-furnace slag 66 to 80 % by
weight) and CEM III/C 32.5 N (content of granulated blast-furnace slag 81 to 95 %
by weight) with higher, the highest, respectively, content of granulated blast-furnace
slag are the most antimicrobially effective especially against fungi with fungistatic
effect.
Industrial Applicability
[0146] Metallurgical slags with activated antimicrobial effects can be used to prevent presence,
growth and reproduction of microorganisms, preferably for building industry. Cements,
building binders, cement containing mixtures, building products and building materials
prepared with them have wide application possibilities from preventive use to maintenance
purposes. They are suitable for obtaining microbially clean environment such as pharmaceutics
productions, medical operation rooms, biochemical laboratories, freezing boxes, cook
houses, laundries, food productions, fruit and vegetable storehouses, animal processing
production, public swimming pools, pools, hygienic facilities and anywhere else where
water, higher humidity or water steam is present. Application is especially advantageous
for maintenance of old moist walls, repairing of houses in flood damaged areas, repairing
of various accidents connected with seepage of water or sewage. They can successfully
be used for building of homes, they are suitable for production of antibacterial and
anti-mould concrete mixtures, masonry mortars and mortars for plastering, dry plastering
mixtures, cement binders, floor mixtures, maintenance cement coatings and other activated
metallurgical slags containing building products.
1. Antimicrobially active agent for building industry characterized in that, it is composed of metallurgical slags.
2. Antimicrobially active agent for building industry according to claim 1, characterized in that, metallurgical slags are antimicrobially activated mechanically and/or chemically.
3. Antimicrobially active agent for building industry according to claim 2, characterized in that, mechanical activation includes change of size of particles, change of granulometry,
of grain distribution of particles, of specific surface, of surface charge of particles,
of surface tension, or of surface energy forces.
4. Antimicrobially active agent for building industry according to claim 2 or 3, characterized in that, mechanical activation is carried out by crushing and/or grinding and/or spreading
and/or separation and/or mixing.
5. Antimicrobially active agent for building industry according to claims 2, 3 or 4,
characterized in that, after mechanical activation, number of particles greater than 500 µm is maximum
99% by weight of overall granulometry.
6. Antimicrobially active agent for building industry according to claims 2, 3, 4 or
5, characterized in that, chemical activation includes modification of chemical composition and/or modification
of mineralogical composition and/or destruction of slag structure and/or excitation
of hydrating reactions and/or excitation of binding processes and/or release of ions
and complex compounds out of slag structure including heavy metals and/or change of
pH and/or change of surface charge and/or phase changes due to hydrating changes and/or
phase changes due to thermal changes.
7. Antimicrobially active agent for building industry according to claims 2, 3, 4, 5
or 6, characterized in that, chemical activation is carried out by addition of activators to slags, cement clinkers,
cements, additives and admixtures used in cement production, in production of concretes,
mortars, dry plastering mixtures, and/or by moistening and/or steaming and/or autoclaving
and/or thermal treatment by drying and/or overheating and/or burning.
8. Antimicrobially active agent for building industry according to claim 7, characterized in that, activators are inorganic and/or organic compounds, e.g. compounds with bound ions
of alkali metals (Na+, K+...) and metals of alkali earths (Ca2+ , Ba2+...).
9. Antimicrobially active agent for building industry according to claim 7 or 8, characterized in that, additives and admixtures used in cement production, are grinding aids, setting regulators,
additives used in production of concretes, mortars, dry plastering mixtures, such
as plasticizers, aeration additives, accelerating additives, inhibiting additives,
lime, lime hydrate, limestone, dolomite, gypsum, anhydrite, plaster.
10. Method of production of antimicrobially active agent for building industry, characterized in that, metallurgical slags are antimicrobially activated mechanically and/or chemically.
11. Method of production of antimicrobially active agent for building industry according
to claim 10, characterized in that, mechanical activation includes change of size of particles, change of granulometry,
of grain distribution of particles, of specific surface, of surface charge of particles,
of surface tension, or of surface energy forces.
12. Method of production of antimicrobially active agent for building industry according
to claim 10 or 11, characterized in that, mechanical activation is carried out by crushing and/or grinding and/or spreading
and/or separation and/or mixing.
13. Method of production of antimicrobially active agent for building industry according
to claims 10, 11 or 12, characterized in that, after mechanical activation, number of particles greater than 500 µm is maximum
99% by weight of overall granulometry.
14. Method of production of antimicrobially active agent for building industry according
to claims 10, 11, 12 or 13, characterized in that, chemical activation includes modification of chemical composition and/or modification
of mineralogical composition and/or destruction of slag structure and/or excitation
of hydrating reactions and/or excitation of binding processes and/or release of ions
and complex compounds out of slag structure including heavy metals and/or change of
pH and/or change of surface charge and/or phase changes due to hydrating changes and/or
phase changes due to thermal changes.
15. Method of production of antimicrobially active agent for building industry according
to claims 10, 11, 12, 13 or 14, characterized in that, chemical activation is carried out by addition of activators to slags, cement clinkers,
cements, additives and admixtures used in cement production, in production of concretes,
mortars, dry plastering mixtures, and/or by moistening and/or steaming and/or autoclaving
and/or thermal treatment by drying and/or overheating and/or burning.
16. Method of production of antimicrobially active agent for building industry according
to claim 15, characterized in that, activators are inorganic and/or organic compounds, e.g. compounds with bound ions
of alkali metals (Na+, K+...) and metals of alkali earths (Ca2+, Ba2+...).
17. Method of production of antimicrobially active agent for building industry according
to claim 15 or 16, characterized in that, additives and admixtures used in cement production, are grinding aids, setting regulators,
additives used in production of concretes, mortars, dry plastering mixtures, such
as plasticizers, aeration additives, accelerating additives, inhibiting additives,
lime, lime hydrate, limestone, dolomite, gypsum, anhydrite, plaster.
18. Use of metallurgical slags according to claims as antimicrobially active agent for
production of cements, building binders, cement containing mixtures, building products
and building materials.
19. Use of metallurgical slags according to claims as antimicrobially active agent for
production of building elements, building parts ,and building constructions.
20. Use metallurgical slags according to claims as antimicrobially active agent for preventing
presence, growth and reproduction of microorganisms.
21. Use of metallurgical slags as antimicrobially active agent for building industry.
22. Use of metallurgical slags according to claim 21, where antimicrobial effect of metallurgical
slags is activated mechanically and/or chemically.
23. Use of metallurgical slags according to claim 22, where mechanical activation includes
change of size of particles, change of granulometry, of grain distribution of particles,
of specific surface, of surface charge of particles, of surface tension, or of surface
energy forces.
24. Use of metallurgical slags according to claim 22 or 23, where mechanical activation
is carried out by crushing and/or grinding and/or spreading and/or separation and/or
mixing.
25. Use of metallurgical slags according to claims 22, 23 or 24, where after mechanical
activation, number of particles greater than 500 µm is maximum 99% by weight of overall
granulometry.
26. Use of metallurgical slags according to claims 22, 23, 24 or 25, where chemical activation
includes modification of chemical composition and/or modification of mineralogical
composition and/or destruction of slag structure and/or excitation of hydrating reactions
and/or excitation of binding processes and/or release of ions and complex compounds
out of slag structure including heavy metals and/or change of pH and/or change of
surface charge and/or phase changes due to hydrating changes and/or phase changes
due to thermal changes.
27. Use of metallurgical slags according to claims 22, 23, 24, 25 or 26, where chemical
activation is carried out by addition of activators to slags, cement clinkers, cements,
additives and admixtures used in cement production, in production of concretes, mortars,
dry plastering mixtures, and/or by moistening and/or steaming and/or autoclaving and/or
thermal treatment by drying and/or overheating and/or burning.
28. Use of metallurgical slags according to claim 27, where activators are inorganic and/or
organic compounds, e.g. compounds with bound ions of alkali metals (Na+, K+...) and metals of alkali earths (Ca2+, Ba2+...).
29. Use of metallurgical slags according to claim 27 or 28, where additives and admixtures
used in cement production, are grinding aids, setting regulators, additives used in
production of concretes, mortars, dry plastering mixtures, such as plasticizers, aeration
additives, inhibiting additives, lime, lime hydrate, limestone, dolomite, gypsum,
anhydrite, plaster.
30. Use of metallurgical slags according to any of preceding claims 21 to 29 for production
of cements, building binders, cement containing mixtures, building products and building
materials.
31. Use of metallurgical slags according to any of preceding claims 21 to 29 for production
of building elements, building parts, and building constructions.
32. Use of metallurgical slags according to any of preceding claims 21 to 29 for preventing
presence, growth and reproduction of microorganisms.